The technique of eXcess eNvelope eNhancement (XNN®) for power amplifiers (PA) is a simplified type of Envelope Tracking (ET), which is a solution for efficient enhancement and power boost of WiFi and WiMAX power amplifiers, as disclosed by U.S. Pat. No. 6,437,641.
A Voltage Enhancement Circuit (VEC™), as disclosed, for example, in U.S. Pat. No. 6,831,519 modulates the supply voltage of power amplifiers as part of the XNN® solution. Appropriate modulation of the supply voltage prevents saturation of power amplifiers while amplifying signals that exceed a predefined programmable threshold. However, the implementation of the circuits disclosed in the above patents are more suitable for using discrete components.
All the methods described above have not yet provided satisfactory solutions to the problem of providing robust implementation a VEC™ in a VLSI chip while overcoming the manufacturing process variations and the chip interactions with other PA system parts.
It is an object of the present invention to propose a method and circuitry for providing robust implementation a VEC™ in a VLSI chip, while overcoming problems that are related to manufacturing process variations and the chip's interactions with other PA system parts.
It is another object of the present invention to propose a method for providing an implementation of a VEC™ in a VLSI chip, while maintaining a relatively fast response time.
Other objects and advantages of the invention will become apparent as the description proceeds.